<?php
/**
 * Created by PhpStorm.
 * User: 氓羽
 * Date: 2018-4-19
 * Time: 22:52
 */
abstract class AA{
    public function Demo(){
        echo "人生若只如初见。";
    }

    public function eat(){}
    public function sing(){}
}

class Person extends AA{
    public function eat()
    {
        echo "继承父类的吃，我很会吃<br />";
    }
    public function sing()
    {
        echo "是不是唱歌，好像是的，哈哈";
    }
}

$p1 =new Person();
$p1->eat();
$p1->Demo();
$p1->sing();